Tamper-evident reclosable bag having slider-actuated string zipper

ABSTRACT

Reclosable bags having a slider-actuated string zipper and a tamper-evident feature. In one aspect, the reclosable bag comprises: a receptacle having a mouth and an interior volume; a string zipper installed in the mouth; a slider mounted to the string zipper; and a tamper-evident feature that blocks access to all or a portion of said interior volume. The tamper-evident feature may take the form of an internal membrane that partitions the interior volume or an external header that covers the string zipper. In some embodiments with a partitioned interior volume, the tamper-evident feature comprises a peel seal.

RELATED PATENT APPLICATION

[0001] This application is a continuation-in-part of and claims priorityfrom U.S. patent application Ser. No. 10/367,450 filed on Feb. 14, 2003and entitled “Reclosable Packaging Having Slider-Operated StringZipper”.

BACKGROUND OF THE INVENTION

[0002] This invention generally relates to reclosable bags havingslider-actuated plastic zippers. In particular, the invention relates toreclosable bags having slider-actuated string zippers.

[0003] In the use of plastic bags, pouches and other packages,particularly for containing foodstuffs, it is important that the bag behermetically sealed and tamper evident until the purchaser acquires thebag and its contents, takes them home, and opens the bag or package forthe first time. It is then commercially attractive and useful for theconsumer that the bag or package be reclosable so that its contents maybe protected. Such bags provide the consumer with the ability to readilystore, in a closed, if not sealed, package any unused portion of thepackaged product even after the package is initially opened. Flexibleplastic zippers have proven to be excellent for reclosable bags, becausethey may be manufactured with high-speed equipment and are reliable forrepeated reuse.

[0004] Many reclosable bags comprise a receptacle having a mouth with aslider-actuated zipper installed therein for opening and closing thebag. As the slider is moved in an opening direction, the slider causesthe zipper sections it passes over to open. Conversely, as the slider ismoved in a closing direction, the slider causes the zipper sections itpasses over to close. Typically, a zipper for a reclosable bag includesa pair of interlockable profiled closure strips that are joined atopposite ends of the bag mouth. The profiles of interlockable plasticzipper parts can take on various configurations, e.g. interlocking riband groove elements having so-called male and female profiles,interlocking alternating hook-shaped closure elements, etc. Reclosablebags having slider-operated zippers are generally more desirable toconsumers than bags having zippers without sliders because the slidereliminates the need for the consumer to align the interlockable zipperprofiles before causing those profiles to engage.

[0005] Various additions to reclosable bags have been made to providetamper-evident seals or indicators that will reveal when the bag hasbeen opened or otherwise tampered with prior to purchase by theconsumer. It is known to provide a reclosable package construction thatis designed to undergo some permanent change in the package appearancewhen the package is opened for the first time. For example, it is knownto provide a reclosable package with a tamper-evident, non-reclosablepeel seal that gives a positive indication of having been broken when apackage is first opened. It is also known to shroud the zipper (with orwithout slider) inside an enclosed header on the top of the bag. Anothertype of tamper-evident feature is the provision of a membrane on theproduct side of the zipper that partitions the interior volume in anairtight manner.

[0006] There is a continuing need for new designs for reclosable bagswith tamper-evident features for hermetic and non-hermetic packages thatcan be manufactured at low cost.

BRIEF DESCRIPTION OF THE INVENTION

[0007] The present invention is directed to reclosable bags that have aslider-actuated string zipper and a tamper-evident feature. Theinvention is further directed to methods of manufacturing such bags.

[0008] One aspect of the invention is a reclosable bag comprising: areceptacle having a mouth and an interior volume; a string zipperinstalled in the mouth; a slider mounted to the string zipper; and atamper-evident feature that blocks access to all or a portion of theinterior volume.

[0009] Another aspect of the invention is a reclosable bag comprising: azipper comprising first and second flangeless zipper strips, the firstzipper strip comprising a first base and a first closure profileprojecting from the first base, and the second zipper strip comprising asecond base and a second closure profile projecting from the second baseand engaged with the first closure profile; a film structure comprising:a first attachment portion joined to the first base of the first zipperstrip; a second attachment portion joined to the second base of thesecond zipper strip, the zipper being disposed between the first andsecond attachment portions of the film structure; a receptacle portionintegrally connected to the first and second attachment portions andhaving an interior volume; and a tamper-evident feature portion havingone side integrally connected to the first attachment portion, thetamper-evident feature portion blocking access to all or a portion ofthe interior volume; and a slider mounted to the zipper and comprisingfirst and second side walls having interior surfaces confrontingopposing portions of the first and second attachment portionsrespectively.

[0010] A further aspect of the invention is a reclosable bag comprising:first and second flangeless zipper strips having mutually interlockableclosure profiles that are joined at opposite ends of the first andsecond zipper strips; a peel seal; a first layer of film materialcomprising a first portion joined to a back of the first flangelesszipper strip, a second portion joined to one side of the peel seal, anda third portion connecting the first and second portions of the firstlayer; a second layer of film material comprising a first portion joinedto a back of the second flangeless zipper strip, a second portion joinedto another side of the peel seal, and a third portion connecting thefirst and second portions of the second layer; a third layer of filmmaterial comprising a portion merged with the first portion of the firstlayer; a fourth layer of film material comprising a portion merged withthe first portion of the second layer, portions of the third and fourthlayers being joined to form a receptacle; and a slider mounted to thefirst and second flangeless zipper strips. The first portion of thefirst layer and the merged portion of the third layer are disposedbetween the back of the first flangeless zipper strip and a confrontingfirst portion of the slider, and the first portion of the second layerand the merged portion of the fourth layer are disposed between the backof the second flangeless zipper strip and a confronting second portionof the slider.

[0011] Yet another aspect of the invention is a reclosable bagcomprising: first and second flangeless zipper strips having mutuallyinterlockable closure profiles that are joined at opposite ends of thefirst and second zipper strips; a peel seal; a first layer of filmmaterial comprising a first portion joined to a back of the firstflangeless zipper strip, a second portion joined to one side of the peelseal, and a third portion connecting the first and second portions; areceptacle comprising second and third layers of film material joinedtogether along a portion of a periphery, the second layer of filmmaterial comprising a portion merged with the first portion of the firstlayer, and the third layer of film material comprising a first portionjoined to a back of the second flangeless zipper strip, a second portionjoined to another side of the peel seal, and a third portion connectingthe first and second portions of the third layer; and a slider mountedto the first and second flangeless zipper strips. The first portion ofthe first layer and the merged portion of the second layer are disposedbetween the back of the first flangeless zipper strip and a confrontingfirst portion of the slider, and the first portion of the third layer isdisposed between the back of the second flangeless zipper strip and aconfronting second portion of the slider.

[0012] A further aspect of the invention is a method of manufacturecomprising the following steps: (a) folding a first portion of amonolithic film structure to form a generally M-shaped gusseted endcomprising first through fourth layers of film material; (b) inserting astring zipper between the second and third layers of the gusseted end;(c) sealing the first and second layers of the gusseted end to eachother and to one side of the string zipper; (d) sealing the third andfourth layers of the gusseted end to each other and to another side ofthe string zipper; and (e) inserting a slider on the string zipper aftersteps (c) and (d).

[0013] Yet another aspect of the invention is a method of manufacturinga reclosable bag, comprising the following steps: (a) arranging andsealing film material to form a receptacle having a mouth and aninterior volume with a tamper-evident feature that blocks access to theinterior volume; (b) prior to completion of the receptacle withtamper-evident feature, joining opposing portions of the film material,that will form the mouth of the receptacle, to respective backs of firstand second flangeless zipper strips; (c) aligning the first and secondflangeless zipper strips with each other; and (d) after steps (b) and(c), mounting a slider onto the aligned first and second flangelesszipper strips with respective portions of the opposing portions of thefilm material being disposed between respective side walls of the sliderand respective backs of the first and second flangeless zipper strips.

[0014] Other aspects of the invention are disclosed and claimed below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a drawing showing a front view of a reclosable bag inaccordance with one embodiment of the present invention. For the purposeof this illustration, it has been assumed that the bag film is opticallytransparent, so that the string zipper and the tamper-evident seal(demarcated by a dashed line) are visible behind a layer of film.

[0016]FIG. 2 is a drawing showing a fragmentary sectional view of aslider-string zipper assembly incorporated in the bag depicted inFIG. 1. The zipper and bag film are shown sectioned in a plane in frontof the closing end of the slider. FIG. 3 is a drawing showing afragmentary sectional view of a string zipper joined to a folded web atan intermediate stage in a manufacturing process in accordance with oneembodiment of the invention.

[0017]FIGS. 4 through 8 are drawings showing successive steps of amethod of making a tamper-evident slider-actuated string zipper packagein accordance with another embodiment of the invention.

[0018]FIGS. 9 through 11 are drawings showing successive steps of amethod of dual manufacture of tamper-evident slider-actuated stringzipper packages loaded with product.

[0019]FIG. 12 is a drawing showing a tamper-evident slider-actuatedstring zipper package in accordance with another embodiment of theinvention.

[0020]FIG. 13 is a drawing showing an alternative construction of atamper-evident slider-actuated string zipper package.

[0021]FIG. 14 is a drawing showing a tamper-evident slider-actuatedstring zipper package in accordance with yet another embodiment of theinvention.

[0022]FIGS. 15 and 16 are drawings showing respective stages in themanufacture of the embodiment depicted in FIG. 13.

[0023]FIG. 17 is a drawing showing a stage in the manufacture of theembodiment depicted in FIG. 12.

[0024] FIGS. 18-22 are drawings showing respective stages in themanufacture of an embodiment of the invention wherein the tamper-evidentfeature is a header.

[0025] Reference will now be made to the drawings in which similarelements in different drawings bear the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

[0026] A reclosable package or bag comprising a receptacle 2 and aflexible plastic string zipper 4 operated by manipulation of a slider 10is shown in FIG. 1. It should be understood that the slider-zipperassemblies disclosed herein can be installed in a reclosable package orbag of the type shown in FIG. 1 or other types of reclosable packageshaving different structures.

[0027] The receptacle 2 may be made from any suitable film material,including thermoplastic film materials such as low-density polyethylene,substantially linear copolymers of ethylene and a C3-C8 alpha-olefin,polypropylene, polyvinylidene chloride, mixtures of two or more of thesepolymers, or mixtures of one of these polymers with anotherthermoplastic polymer. The person skilled in the art will recognize thatthis list of suitable materials is not exhaustive. The receptacle 2comprises opposing walls (only the front panel is visible in FIG. 1)that may be secured together at opposite side edges of the bag by seams60 and 62 (indicated by dashed lines). The opposing bottoms of the wallsmay be joined, for example, by means of a heat seal 64 (indicated by adashed line) made in conventional fashion, e.g., by application of heatand pressure.

[0028] At its top end, the receptacle 2 has an openable mouth, on theinside of which is an extruded plastic string zipper 4. The stringzipper 4 comprises a pair of interlockable zipper strips 6 and 8 (bestseen in FIG. 2). Although FIG. 2 shows a rib and groove arrangement, theprofiles of the zipper halves may take any form. For example, the stringzipper may comprise interlocking rib and groove elements (as shown inFIG. 2) or alternating hook-shaped closure elements. The preferredzipper material is polyethylene or polypropylene. The string zipper 4 isoperated by sliding the slider 10 along the zipper strips. As the slidermoves across the zipper, the zipper is opened or closed. As shown inFIG. 1, the slider is slidable along the zipper in a closing direction“C”, causing the zipper strips to become engaged, or in an openingdirection “O”, causing the zipper strips to become disengaged.

[0029] Referring again to FIG. 1, the string zipper 4 further comprisesend stops 66 and 68 for preventing the slider 10 from sliding off theend of the zipper when the slider reaches the zipper closed or fullyopened position. Typically, the end stops are formed by fusing the endsof the zipper strips together while at the same time shaping the fusedmaterial into an end stop structure. Such end stops perform dualfunctions, serving as stops to prevent the slider from going off the endof the zipper and also holding the two zipper profiles together toprevent the bag from opening in response to stresses applied to theprofiles through normal use of the bag. However, the present inventionis not limited to the incorporation of a slider end stop structure ofany particular type.

[0030] In accordance with various embodiments of the present invention,a tamper-evident seal (or feature) is formed in the interior of the bagon the product side of the string zipper. In one embodiment, thetamper-evident seal takes the form of a U-shaped or V-shaped membrane ofbag making film that is suspended from the zipper on the product sidethereof. In FIG. 1, the dashed line 44 demarcates the cusp of such a U-or V-shaped membrane. One side of the membrane is joined to the back ofone zipper strip, while the other side of the membrane is joined to theback of the other zipper strip. The ends of the membrane 44 are capturedin the side seals 60 and 62, thereby hermetically sealing the interiorvolume of the bag. [Alternatively, in cases where a hermetic seal is notrequired, the membrane does not need to be joined at its ends to theside seals of the bag.] To have access to the contents of the bag, theuser must first open the zipper by moving the slider and then tear openthe membrane 44 disposed inside the bag.

[0031] The structure of the bag in accordance with some embodiments ofthe invention is shown in detail in FIG. 2. The membrane 44 comprises afirst layer of film material that has been folded into a U- or V-shapeand that has respective marginal portions joined (e.g., by conductionheat sealing) to the backs of a pair of interlocked flangeless zipperstrips 6 and 8. A second layer of the same film material, having amarginal portion merged with one marginal portion of the first layer,forms a front wall 2 a of the receptacle 2, while a third layer of thesame film material, having a marginal portion merged with the othermarginal portion of the first layer, forms a rear wall 2 b of thereceptacle 2. [The merged portions of the first, second and third layersof film material are depicted as being distinct layers in FIGS. 2 and 3for the purpose of illustration only. In reality, the interface betweenthe melted layers of film would be less distinct, if notindistinguishable.] The front and rear walls 2 a and 2 b are typicallysealed together along three sides (as illustrated in FIG. 1) to form thereceptacle. At the same time, the marginal portions on the sides of thefolded first layer of film material may be captured in the side seals ofthe receptacle. As a result, the membrane 44 will form a tamper-evidenthermetic seal.

[0032] Still referring to FIG. 2, the string zipper comprises a pair ofinterlockable zipper parts or strips 6 and 8. Although FIG. 2 shows arib and groove arrangement, the profiles of the zipper strips may takeany form. For example, the string zipper may comprise interlocking riband groove elements (as shown in FIG. 2) or alternating hook-shapedclosure elements. The preferred zipper material is polyethylene orpolypropylene. The merged marginal portions of the membrane 44 and thereceptacle walls 2 a and 2 b may be respectively sealed to the backs ofthe zipper strips 6 and 8 by a conventional conduction heat sealingtechnique.

[0033] After the film material has been joined to the string zipper andany excess film beyond the zipper has been trimmed, a slider is insertedon the string zipper. In the example depicted in FIG. 2, the slider hasa separating finger or plow 42 that projects into an opening betweenopposing sections of the zipper strips.. To open more zipper, the zipperstrips 6 and 8 are pushed apart with sufficient force by the slider plow42 to pry the heads of the male members out of the female profiles. Whenthe shoulders of the male members clear the hooks of the outwardlyflexed gripper jaws, the male and female members are no longerinterlocked and the zipper is open.

[0034]FIG. 3 shows a stage in the manufacture of the bag partiallydepicted in FIG. 2. In accordance with this method of manufacture, onestarts with a single web of film material that is folded three times toform an M-shaped gusseted end. The string zipper is inserted into thegusset (at a distance from the cusp of the gusset) and then the film isheat sealed to the string zipper on both sides to form merged doublelayers 3 and 3′. A pair of hot sealing bars 80 and 82 is generallyrepresented by rectangles spaced on opposing sides of the zipper. Thesealing bars reciprocate between retracted positions (seen in FIG. 3)and extended positions (not shown). Heat sealing occurs when theextended sealing bars 80 and 82 press the double layers of film materialagainst the respective backs of flangeless zipper strips 6 and 8. Thesealing bars form band-shaped zones of joinder. After sealing of thedouble layers to the zipper, the folded edges 72 and 74 may extend abovethe zipper on respective sides thereof. These folded loops will later betrimmed by cutting along cut lines 76 and 78. After trimming of thefolded edges 72 and 74, the upper margins of the double layers of bagfilm may have short free ends (below the cut lines 76 and 78 depicted inFIG. 3) that extend above the zones of joinder, provided that these freeends are not so long as to interfere with travel of the slider along thezipper or become entangled with the zipper profiles. Alternatively, thefolds 72 and 74 may be sufficiently aligned with the zipper strips 6, 8that no trimming is necessary.

[0035] The zipper in this example is an extruded plastic structurecomprising mutually interlockable profiled flangeless zipper strips 6and 8. Zipper strip 8 comprises a base and two generally arrow-shapedrib-like male closure elements or members 20 and 28 projecting from abase 14, while zipper strip 6 comprises two pairs of hook-shaped gripperjaws connected by a sealing bridge 12. The pairs of gripper jaws formrespective complementary female profiles for receiving the male profilesof closure elements 20 and 28. More specifically, jaws 16 and 18 receiveand interlock with the male element 20, while jaws 22 and 24 receive andinterlock with the male element 28. The sealing bridge 12 and the base14 are resiliently flexible self-supporting structures having athickness greater than the thickness of the bag film. The male closureelements are integrally formed with the base 14, while the femaleclosure elements are integrally formed with the sealing bridge 12.

[0036] Still referring to FIG. 3, the end face of upper edge 30 of thebase 14 that carries the male closure elements 20 and 28 is inclined atabout a 45° angle to facilitate loading of the slider onto the zipperfrom above without snagging on a corner of the upper edge. The bottomedge of the base 14 cooperates with a retaining ledge on the slider toincrease the slider pull-off resistance. For the same purpose, a rib 26is formed on zipper part 6, the rib 26 cooperating with a retainingledge on the other side of the slider.

[0037] Numerous configurations for the interlockable male and femalemembers are known in the art. The present invention is not limited touse with male members having an arrow-shaped head. In addition, althoughFIGS. 2 and 3 show a rib-and-groove arrangement, the profiles of thezipper strips may take any form. For example, either string zipper maycomprise alternating hook-shaped closure elements.

[0038] The slider 10 shown in FIG. 2 is fully disclosed in U.S. patentapplication Ser. No. 10/367,450 and comprises a top wall 32, a pair ofside walls 34 and 36 connected to opposing sides of the top wall 32, thetop wall 32 and side walls 34, 36 forming a tunnel for passage of thestring zipper therethrough. The width of the tunnel is substantiallyconstant along the section that is divided by a plow 42 and then narrowsfrom a point proximal to the end of the plow to the closing window atone end face of the slider. The plow 42 depends downward from a centralportion of the top wall 32 to an elevation below the lowermost portionsof each side wall, and has rounded edges and flattened comers at the tipto facilitate insertion of the plow between the zipper profiles withoutsnagging during automated slider insertion. As the slider is moved inthe opening direction (i.e., with the closing end leading), the plow 42pries the impinging sections of zipper strips 6 and 8 apart. Thenarrowing section of the slider tunnel is formed by a pair ofsubstantially planar, inclined interior surfaces (not visible in FIG.2), which converge toward the closing window of the slider. The inclinedsurfaces funnel or squeeze the zipper strips toward each other, causingthe zipper profiles to interlock, as the slider is moved in the closingdirection.

[0039] As partly seen in FIG. 2, the slider 10 further comprises aretaining projection or ledge 38 that projects inward from the side wall34 and a retaining projection or ledge 40 that projects inward from theside wall 36. The ledges 38 and 40 project toward each other, formingrespective latches for latching the slider onto the zipper. The ledges38 and 40 further comprise respective generally planar, inclined bottomsurfaces 50 and 52 that serve to guide the respective zipper strips 6and 8 into the slider tunnel during automated slider insertion.

[0040] To reduce the cost of manufacture, the slider may be designed toreduce the amount of material used and to increase the speed with whichsuch sliders can be injection molded. Suitable injection-molded sliderdesigns are fully disclosed in U.S. patent application Ser. No.10/412,438 entitled “Molded Sliders for Actuating Zippers in ReclosableBags”.

[0041] The reclosable bags with tamper-evident features andslider-actuated string zippers disclosed herein do not require that theslider have a separating finger. Sliders without separating fingers canalso be employed, provided that the zipper strips are suitably designedto be actuated by such sliders.

[0042] Reclosable packages of the type partially depicted in FIG. 2 canbe manufactured on an automatic production line. In this particularcase, the steps of the method of manufacture carried out by suchequipment comprise the following steps: First, a web of bag making filmis folded along three fold lines to form a generally M-shaped gussetedend comprising first through fourth layers of film material. A stringzipper is then inserted at an angle into the space between the twocentral (i.e., second and third) layers of the gusset. At a zippersealing station, a section of zipper is sealed to both sides of thegusset, i.e., the first and second layers of the gusset are sealed toeach other and to the back of one flangeless zipper strip; while thethird and fourth layers of the gusset are sealed to each other and tothe back of the other flangeless zipper strip. At the same time, theopposing marginal edges of the folded web of bag making film can beband-sealed together. This seal will become the bottom of the bag. Afterzipper sealing, the folded edges above the zones of joinder are trimmed,e.g., by stationary knives as the web with zipper is moving. Aftertrimming, a slider is inserted onto the string zipper by a sliderinsertion device and the zipper is ultrasonically stomped to form sliderend stops. A suitable apparatus for inserting sliders onto string zippermaterial with attached bag making film is fully disclosed in U.S. patentapplication Ser. No. 10/436,433 entitled “Method and Apparatus forInserting Sliders During Automated Manufacture of Reclosable Bags”. Theweb is then cut by a hot knife in a transverse direction, the cuttingline bisecting the ultrasonically stomped region. The hot knifesimultaneously severs the film and zipper and seals the film along thecut edges. Alternatively, product can be placed between the two sides ofthe folded web before the opposing marginal edges of the web areband-sealed together. In accordance with a further aspect of theinvention, a line of weakened tear resistance (e.g., a line of spacedperforations) can be formed in the web prior to folding, the tear linebeing located such that it is at or near the cusp of the gusset afterfolding.

[0043] An alternative method for manufacturing a reclosable bag having aslider-actuated string zipper and a tamper-evident seal on the productside of the zipper is depicted in FIGS. 4-8. First, a web 90 of bagmaking film is folded along three fold lines to form a generallyM-shaped gusseted end comprising first through fourth layers of filmmaterial, as shown in FIG. 4. The other end of the web is left open.Optionally, a line of weakened tear resistance may be formed in the webalong a centerline before folding. As a result of the folding operation,this line 45 of weakened tear resistance will be located at the cusp ofthe gusset. In cases where a hermetic seal is required, the line ofweakened tear resistance may take the form of a scoreline. If a hermeticseal is not required, then a line of spaced perforations could be used.

[0044] After folding, a separator plate 84 is inserted into the gussetin the area where the string zipper will be joined, as shown in FIG. 5.A pair of heated sealing bars 80 and 82, shown in respective retractedpositions in FIG. 5, are then extended until the faces of the sealingbars respectively press the respective layers of folded film against theseparator plate 84 from opposite sides thereof. During this operation,the marginal portions of the first and second film layers of the foldedweb are heat sealed together on one side of the separator plate 84,while the marginal portions of the third and fourth film layers of thefolded web are heat sealed together on the other side of the separatorplate 84. The separator plate 84 prevents the sealing together of thesecond and third film layers that form the gusset.

[0045] In the next stage of manufacture, one fold is lifted up, or moreexactly, pivoted from a generally horizontal position to a generallyvertical position, as shown in FIG. 6, by a deflector 86. Then thestring zipper 4 is introduced, e.g., by laying string zipper on top ofthe sealed portion of the fold that was not lifted up, the zipper beingdisposed proximal and parallel to the edge of the fold. The upliftedfold is then returned to its original position (this step is not shownin the drawings), in which case the zipper 4 will now be sandwichedbetween the respective sealed portions of the respective fold onopposite sides of the gusset. At a zipper sealing station, another pairof heated sealing bars 94 and 96 (shown in their respective retractedpositions in FIG. 7) are then extended into contact with the sealed(i.e., merged) double layers of film on opposite sides of the stringzipper 4. During this operation, the merged double layer of film on oneside of the gusseted end is joined to the back of one flangeless zipperstrip, while the merged double layer of film on the other side of thegusseted end is joined to the back of the other flangeless zipper strip.After the zipper has been attached to the folded web, a slider 10 (seeFIG. 8) is inserted over the zipper and respective joined film layers.If due to the difficulty of precisely aligning the string zipper withthe edges of the merged double layers of film, portions of the mergedfilm extend beyond the zones of joinder of film to zipper, thoseportions can be trimmed to prevent interference with the operation ofthe slider-zipper assembly.

[0046]FIGS. 9 through 11 show successive steps of a method of dualmanufacture of tamper-evident slider-actuated string zipper packagesloaded with product in accordance with a further embodiment of theinvention. Starting with a tube of film, the film is folded to formrespective M-shaped gusseted ends at diametrally opposite positions, thefolding operation at each end being similar to that described previouslywith reference to FIG. 4. The marginal portions of the outer folds ofeach gusseted end are then sealed together using separator plates andheated sealing bars in the manner generally described previously withreference to FIG. 5. Then a respective sealed fold at each gusseted endis pivoted to a respective upright position and a respective stringzipper is introduced onto the sealed folds that were not uplifted, inthe manner previously described with reference to FIG. 6.

[0047] The uplifted folds of tubing 91 are then restored to respectivehorizontal positions overlying the respective string zippers, as shownin FIG. 9. Each string zipper 4 and 4′ is then joined to the mergeddouble layers of film that sandwich the zipper. More precisely, theheated sealing bar 94 joins the sealed fold 98 to the back of oneflangeless zipper strip of zipper 4; the heated sealing bar 96 joins thesealed fold 100 to the back of the other flangeless zipper strip ofzipper 4; the heated sealing bar 94′ joins the sealed fold 102 to theback of one flangeless zipper strip of zipper 4′; and the heated sealingbar 96′ joins the sealed fold 104 to the back of the other flangelesszipper strip of zipper 4′. In a separate operation, the film tubing 91is cut along a cutting line 106 that runs generally parallel to andequidistant from the zippers at opposite ends of the tubing. Asexplained below, this cutting operation allows product to be loaded.Although FIG. 9 depicts concurrent film cutting and zipper sealingoperations, a person skilled in the art will recognize that the filmcould be cut after the zipper have been attached.

[0048] After the tubing 91 has been cut, the upper flaps 108, 110 offilm on opposite sides of the cut are raised and wrapped around astationary feeding platform 112 (the zipper-film assembly is moving).The wrapped positions of the film relative to the feeding platform areshown in FIG. 10. Respective masses 114 and 114′ of product are loadedonto the bottom layer of film via the feeding platform. Respectivesliders 10 and 10′ are inserted on the respective string zippers 4 and4′. Although FIG. 10 depicts concurrent product loading and sliderinsertion operations, a person skilled in the art will recognize thatthe sliders could be inserted before or after the product is loaded. Theproduct masses are placed between the zippers and separated from eachother by a space where the film will be sealed by a heated sealing bar116, as shown in FIG. .11. Later the seal 118 will be cut down themiddle and the film will be cross cut and sealed to form separate sealedpackages, each package being loaded with product and having atamper-evident seal 120, 120′. It should be understood that instead oftubing, a flat film can be folded in a manner that will provide the samefilm configuration as that of the tubing, and that the method ofattaching a zipper can be as previously described.

[0049]FIG. 12 shows a tamper-evident slider-actuated string zipperpackage in accordance with another embodiment of the invention. Two webs125 and 126 of bag making film are folded inward to form two short flaps122, 124 that are in mutual opposition. The unfolded ends of the webs125 and 126 are joined by a fin seal 127, which will serve as the bottomof the receptacle. A peel seal 128 is joined to the opposing marginalportions of the flaps 122 and 124, forming a tamper-evident seal. Thefilm layers of the folds 130, 132 are sealed together and these mergeddouble layers of film are in turn joined to the respective backs of theflangeless zipper strips of the string zipper 4. A slider 10 is insertedon the string zipper with the merged layers of the outer folds beingrespectively disposed between the zipper strips and the side walls ofthe slider, in the manner depicted in FIG. 2.

[0050]FIG. 13 shows an alternative construction of a tamper-evidentslider-actuated string zipper package. This construction differs fromthe construction in FIG. 12 in that only web 125 of bag making film isfolded inward to form a solitary inward flap 122. In this case, the peelseal 128 joins the marginal portion of the flap 122 to a band-shapedzone on the opposing wall of the receptacle, thus forming atamper-evident seal. Also, this embodiment differs from the embodimentof FIG. 12 in that one side of the string zipper 4 is joined to a singlelayer of film, i.e., the marginal portion 134 of the wall that is joinedto the peel seal 128, while the other side of the string zipper isjoined to a double layer of merged film material, as previouslydescribed. The edges of the film that extend beyond the zone ofzipper-film joinder can be trimmed as needed (which is true for allembodiments disclosed herein). Instead of a peel seal, the marginalportion of the flap 122 can be hard sealed to the opposing receptaclewall with a line of weakened tear resistance being provided in the flap.

[0051] Alternatively, a single web of film could be folded a first timeto form the bottom of the bag and a second time to form the foldeddouble layer that is sealed to one zipper strip. The end result would bea reclosable bag similar in structure to that shown in FIG. 13, butwithout the fin seal 127 at the bag bottom. The manufacture of thisalternative embodiment would involve treating the back edge of theinward flap (on the other side of the peel seal) in a way that wouldprevent seal through during activation of the peel seal. In this case,the peel seal could activated after the slider has been loaded.

[0052] In accordance with a further alternative, a web of film could befolded once to form a U-shape and then a separate strip of film could besealed to the inside of one wall of the folded web to form the flap 122seen in FIG. 13. However, the feeding of separate webs or strips of filmand then joining them along a margin requires that the respectivetensions in the separate webs or strips be separately controlled to berelatively equal.

[0053] Similarly, instead of folding a web of film to form an M-shapedgusseted end, as previously described with reference to FIG. 3, separatewebs 136, 138 of film of different width can each be folded intorespective U-shapes, as shown in FIG. 14. Then the short folded web 136is inserted between the sides of the long folded web 138 with theiredges respectively aligned. Next, a string zipper 4 is inserted betweenmarginal portions of the short folded web 136. The marginal portions ofthe long and short folded webs are then heat sealed to the backs of theflangeless strips of the string zipper to form merged double layers 140,142 of film of the type seen in FIG. 3. The fold 144 in the long foldedweb forms the bottom of the receptacle, while the fold 146 in the shortfolded web forms the cusp of a tamper-evident-seal. The web of shortwidth can be perforated or scored along a centerline to form a line ofweakened tear resistance at or near the cusp of the tamper-evident seal.The end result is that the final bag will have substantially the samestructure as the bag partially depicted in FIG. 2, except that thebottom of the receptacle is formed by a fold 144 instead of a heat seal.

[0054] In accordance with a further variation, the same structuredepicted in FIG. 14 can be attained starting with a tube of film that isfolded to form an M-shaped gusset. Then the double layers of film onopposing sides of the gusset are sealed to opposite sides of a stringzipper in the manner previously described. If the gusset edges need tobe trimmed, then the final structure would be identical to that shown inFIG. 14. If the outer fold lines are sufficiently aligned with thezipper strips, then the folded edges would not need to be trimmed.

[0055] In the case of the embodiment shown in FIG. 13, dual manufacturecan be achieved by a method comprising the steps depicted in FIGS. 15and 16 and other steps not depicted in the drawings. First, respectivestrips of peel seal material 128 are joined in parallel to respectivemarginal portions on opposite sides of a film web 150. Then, as depictedin FIG. 15, a marginal portion of a second film web 146 is placed inoverlying relationship with and then joined to the peel seal material128 on one side of web 150, and a marginal portion of a second film web148 is placed in overlying relationship with and then joined to the peelseal material 128 on the other side of web 150. If the finished bags areto be loaded with product, then before the webs 146 and 148 are foldedover (indicated by dashed lines), respective masses of product 114 and114′ are placed on the web 150 at locations between the peel seals 128.The webs 146 and 148 are folded along lines located laterally outward ofthe respective peel seals.

[0056] As shown in FIG. 16, respective string zippers 4 are placedbetween respective marginal portions of web 150 and opposing respectivefolded-over portions of webs 146 and 148. The film material on opposingsides of the string zippers 4 is sealed thereto by heated sealing bars(not shown), a respective double layer of film being joined on one sideof each string zipper and a respective single layer of film being joinedon the other side of each string zipper, as seen in FIG. 16. In anothersealing operation, the free ends of the folded-over webs 146 and 148 arejoined to a central portion of web 150, the resulting seal 152 beingdisposed along a centerline of web 150 that runs between the respectivemasses of product 114 and 114′. After the string zippers have beenjoined to the film, sliders (not shown) are inserted. When the assemblydepicted in FIG. 16 is cross sealed and cut along a transverse line andthen cut along the centerline, bisecting the central seal 152, twofinished filled packages come off of the production line.

[0057] The embodiment shown in FIG. 12 is susceptible to dualmanufacture in a similar manner, except the web 150 is folded inward onboth sides and then the lengths of peel seal material 128 are applied tothe inwardly folded flaps, as shown in FIG. 17. To prevent seal-throughof the portions of web 150 located below the peel seal material,respective separating plates 154 and 154′ are inserted between theoverlapping portions of web 150 during joinder of the peel seal materialto the inwardly folded flaps by application of heat. Thereafter, webs146 and 148 are loaded with product, folded and sealed, string zippersare sealed in place, and sliders are inserted in the manner previouslydescribed with reference to FIGS. 15 and 16.

[0058] A method for manufacturing an embodiment of the invention whereinthe tamper-evident feature comprises a header is partially depicted inFIGS. 18-22. As shown in FIG. 18, a web 156 of film material is foldedalong three fold lines to form a serpentine profile comprising a pair ofinner legs 157 and 159, and a pair of outer legs 158 and 160. The outerleg 158 is connected to the inner leg 157 at the first fold line; theinner leg 157 is connected to the inner leg 159 at the second fold line;and the inner leg 159 is connected to the outer leg 160 at the thirdfold line. Referring to FIG. 19, the confronting portions of outer leg158 and inner leg 157 proximal to the first fold line are heat sealedtogether to form a merged double layer of film 130; likewise theconfronting portions of outer leg 160 and inner leg 159 proximal to thethird fold line are heat sealed together to form a merged double layerof film 132. In the next step, a string zipper 4 is placed between therespective merged portions 130 and 132, and the latter are respectivelyjoined (e.g., by heat sealing) to opposite sides of the string zipper(i.e., the bases of respective complementary flangeless zipper strips),as seen in FIG. 20. Then a slider is inserted over the string zipper andthe film material joined thereto (see FIG. 21). The outer legs 158 and160 are then folded over the zipper so that the marginal portions of theouter legs are in confronting relationship. The confronting marginalportions of outer legs 158 and 160 are then heat sealed to form a finseal 162 (see FIG. 22). The resulting header can be open at both endsor, if a hermetic seal is desired, sealed shut at both ends. Thereafter,the assembly shown in FIG. 22 can be cross sealed and cut along atransverse line to sever a finished package from the work in progress.Product can be placed on the web of film material 156 before the web isfolded, or the space between the inner legs can be filled before thezipper is applied. Alternatively, after zipper application and sliderinsertion, product can be loaded when the zipper is open, or the filmcan be slit to allow the product to be loaded, after which the slit isresealed.

[0059] Although not shown in FIG. 22, a respective line of weakened tearresistance can be formed in each outer leg 158, 160, the lines beingparallel to the zipper and below the slider, to facilitate removal ofthe header by a consumer. Each line of weakened tear resistance maycomprise a series of spaced perforations (for non-hermetic headers) or ascoreline (for hermetic headers). The lines of weakened tear resistancecan be formed in the web 156 before or after the header is formed.Additionally, the header could be provided with a hang hole.

[0060] The invention does not require that the slider have a plow orseparating finger. The slider-zipper assembly could be designed so thatthe side walls of a straddling slider cam or push the zipper open,without the aid of a plow or separating finger, when the slider is movedin an opening direction.

[0061] While the invention has been described with reference topreferred embodiments, it will be understood by those skilled in the artthat various changes may be made and equivalents may be substituted formembers thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationto the teachings of the invention without departing from the essentialscope thereof. Therefore it is intended that the invention not belimited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

[0062] As used in the claims, the verb “joined” means fused, bonded,sealed, adhered, etc., whether by application of heat and/or pressure,application of ultrasonic energy, application of a layer of adhesivematerial or bonding agent, interposition of an adhesive or bondingstrip, etc. As used in the claims, the term “string zipper” means azipper comprising two interlockable closure strips that havesubstantially no flange portions.

1. A reclosable bag comprising: a receptacle having a mouth and aninterior volume; a string zipper installed in said mouth; a slidermounted to said string zipper; and a tamper-evident feature that blocksaccess to all or a portion of said interior volume.
 2. The bag asrecited in claim 1, wherein said tamper-evident feature comprises alayer of film material.
 3. The bag as recited in claim 2, wherein saidtamper-evident feature further comprises a peel seal.
 4. The bag asrecited in claim 2, wherein said receptacle and said tamper-evidentfeature have respective first portions that are merged together andjoined to one side of said string zipper.
 5. The bag as recited in claim4, wherein said receptacle and said tamper-evident feature haverespective second portions that are merged together and joined toanother side of said string zipper.
 6. The bag as recited in claim 5,wherein said first portion of said receptacle is sandwiched between saidfirst portion of said tamper-evident feature and said string zipper,said second portion of said receptacle is sandwiched between said secondportion of said tamper-evident feature and said string zipper, and saidtamper-evident feature further comprises third and fourth portionsrespectively integrally connected on one side to said first and secondportions of said tamper-evident feature, the other side of said thirdportion of said tamper-evident feature being joined to the other side ofsaid fourth portion of said tamper-evident feature to form a cover oversaid zipper.
 7. The bag as recited in claim 5, wherein said firstportion of said tamper-evident feature is sandwiched between said firstportion of said receptacle and said string zipper, said second portionof said tamper-evident feature is sandwiched between said second portionof said receptacle and said string zipper, and said tamper-evidentfeature further comprises a third portion having one side integrallyconnected to said first portion of said tamper-evident feature andanother side integrally connected to said second portion of saidtamper-evident feature, respective ends of said third portion beingjoined to said receptacle to form a sealed space inside said interiorvolume for product.
 8. The bag as recited in claim 5, wherein said firstportion of said tamper-evident feature is sandwiched between said firstportion of said receptacle and said string zipper, said second portionof said tamper-evident feature is sandwiched between said second portionof said receptacle and said string zipper, and said tamper-evidentfeature further comprises third and fourth portions respectivelyintegrally formed on one side with said first and second portions ofsaid tamper-evident feature, and a peel seal joined to the other sidesof said third and fourth portions of said tamper-evident feature.
 9. Thebag as recited in claim 4, wherein said first portion of saidtamper-evident feature is sandwiched between said first portion of saidreceptacle and said string zipper, and said tamper-evident featurefurther comprises a second portion integrally formed on one side withsaid first portion of said tamper-evident feature, and a peel sealjoined to the other side of said second portion of said tamper-evidentfeature and to said receptacle.
 10. The bag as recited in claim 4,wherein said first portion of said tamper-evident feature is sandwichedbetween said first portion of said receptacle and said string zipper,and said tamper-evident feature further comprises a second portionintegrally formed on one side with said first portion of saidtamper-evident feature and fused on the other side to said receptacle.11. The bag as recited in claim 10, wherein said second portion of saidtamper-evident feature comprises a line of weakened tear resistance. 12.The bag as recited in claim 1, wherein said tamper-evident featurecomprises a header joined to said receptacle and covering said zipper.13. The bag as recited in claim 1, wherein said tamper-evident featurecomprises a membrane joined to said receptacle in a manner thatpartitions said interior volume.
 14. The bag as recited in claim 13,wherein said membrane comprises a line of weakened tear resistance. 15.The bag as recited in claim 13, further comprising a mass of productdisposed in said interior volume of said receptacle.
 16. A reclosablebag comprising: a zipper comprising first and second flangeless zipperstrips, said first zipper strip comprising a first base and a firstclosure profile projecting from said first base, and said second zipperstrip comprising a second base and a second closure profile projectingfrom said second base and engaged with said first closure profile; afilm structure comprising: a first attachment portion joined to saidfirst base of said first zipper strip; a second attachment portionjoined to said second base of said second zipper strip, said zipperbeing disposed between said first and second attachment portions of saidfilm structure; a receptacle portion integrally connected to said firstand second attachment portions and having an interior volume; and atamper-evident feature portion having one side integrally connected tosaid first attachment portion, said tamper-evident feature portionblocking access to all or a portion of said interior volume; and aslider mounted to said zipper and comprising first and second side wallshaving interior surfaces confronting opposing portions of said first andsecond attachment portions respectively.
 17. The bag as recited in claim16, wherein the other side of said tamper-evident feature portion isintegrally connected to said second attachment portion, saidtamper-evident feature portion forming a header that covers said zipper.18. The bag as recited in claim 17, wherein said tamper-evident featureportion comprises first and second header walls that are joined togetheralong opposing portions proximal to respective edges of said first andsecond header walls.
 19. The bag as recited in claim 16, wherein theother side of said tamper-evident feature portion is integrallyconnected to said second attachment portion, and the ends of saidtamper-evident feature portion are joined to said receptacle portion ina manner that partitions said interior volume.
 20. The bag as recited inclaim 19, wherein said tamper-evident feature portion comprises a lineof weakened tear resistance.
 21. The bag as recited in claim 16, furthercomprising a mass of product disposed in said interior volume of saidreceptacle portion.
 22. The bag as recited in claim 16, wherein each ofsaid first and second attachment portions has a thickness greater than athickness of either said tamper-evident feature portion or saidreceptacle portion.
 23. The bag as recited in claim 16, wherein saidreceptacle portion comprises first and second receptacle walls that arejoined together along opposing portions proximal to respective edges ofsaid first and second receptacle walls.
 24. The bag as recited in claim16, wherein the other side of said tamper-evident feature portion andthe ends of said tamper-evident feature portion are joined to saidreceptacle portion in a manner that partitions said interior volume. 25.The bag as recited in claim 24, wherein said tamper-evident featureportion comprises a line of weakened tear resistance.
 26. A reclosablebag comprising: first and second flangeless zipper strips havingmutually interlockable closure profiles that are joined at opposite endsof said first and second zipper strips; a peel seal; a first layer offilm material comprising a first portion joined to a back of said firstflangeless zipper strip, a second portion joined to one side of saidpeel seal, and a third portion connecting said first and second portionsof said first layer; a second layer of film material comprising a firstportion joined to a back of said second flangeless zipper strip, asecond portion joined to another side of said peel seal, and a thirdportion connecting said first and second portions of said second layer;a third layer of film material comprising a portion merged with saidfirst portion of said first layer; a fourth layer of film materialcomprising a portion merged with said first portion of said secondlayer, portions of said third and fourth layers being joined to form areceptacle; and a slider mounted to said first and second flangelesszipper strips, said first portion of said first layer and said mergedportion of said third layer being disposed between said back of saidfirst flangeless zipper strip and a confronting first portion of saidslider, and said first portion of said second layer and said mergedportion of said fourth layer being disposed between said back of saidsecond flangeless zipper strip and a confronting second portion of saidslider.
 27. The bag as recited in claim 26, wherein said receptacle hasan interior volume that is sealed closed by said first and second layersof film material when said peel seal is intact.
 28. The bag as recitedin claim 26, wherein said first through fourth layers are sealedtogether at respective sides of said receptacle.
 29. A reclosable bagcomprising: first and second flangeless zipper strips having mutuallyinterlockable closure profiles that are joined at opposite ends of saidfirst and second zipper strips; a peel seal; a first layer of filmmaterial comprising a first portion joined to a back of said firstflangeless zipper strip, a second portion joined to one side of saidpeel seal, and a third portion connecting said first and secondportions; a receptacle comprising second and third layers of filmmaterial joined together along a portion of a periphery, said secondlayer of film material comprising a portion merged with said firstportion of said first layer, and said third layer of film materialcomprising a first portion joined to a back of said second flangelesszipper strip, a second portion joined to another side of said peel seal,and a third portion connecting said first and second portions of saidthird layer; and a slider mounted to said first and second flangelesszipper strips, said first portion of said first layer and said mergedportion of said second layer being disposed between said back of saidfirst flangeless zipper strip and a confronting first portion of saidslider, and said first portion of said third layer being disposedbetween said back of said second flangeless zipper strip and aconfronting second portion of said slider.
 30. The bag as recited inclaim 29, wherein said receptacle has an interior volume that is sealedclosed by said first layer of film material when said peel seal isintact.
 31. The bag as recited in claim 29, wherein said first throughthird layers are sealed together at respective sides of said receptacle.32. A method of manufacture comprising the following steps: (a) foldinga first portion of a monolithic film structure to form a generallyM-shaped first gusseted end comprising first through fourth layers offilm material; (b) inserting a first string zipper between said secondand third layers of said first gusseted end; (c) sealing said first andsecond layers of said first gusseted end to each other and to one sideof said first string zipper; (d) sealing said third and fourth layers ofsaid first gusseted end to each other and to another side of said firststring zipper; and (e) inserting a first slider on said first stringzipper after steps (c) and (d).
 33. The method as recited in claim 32,further comprising the step of sealing respective portions of saidmonolithic film structure together along a portion of a first peripheryto form a first enclosed receptacle.
 34. The method as recited in claim33, further comprising the step of placing a first mass of product on afirst non-peripheral portion of said monolithic film structure beforesaid first enclosed receptacle is formed, said first mass of productbeing contained inside said first enclosed receptacle when the bag isfinished.
 35. The method as recited in claim 32, further comprising thestep of weakening the tear resistance of said monolithic film structurealong a line before said folding step, said line of weakened tearresistance being located so that it will be proximal to a central foldof said first gusseted end after said folding step.
 36. The method asrecited in claim 32, further comprising the step of trimming unsealedfilm material at the peaks of said generally M-shaped first gussetedend.
 37. The method as recited in claim 34, further comprising thefollowing steps: (f) folding a second portion of said monolithic filmstructure to form a generally M-shaped second gusseted end comprisingfirst through fourth layers of film material; (g) inserting a secondstring zipper between said second and third layers of said secondgusseted end; (h) sealing said first and second layers of said secondgusseted end to each other and to one side of said second string zipper;(i) sealing said third and fourth layers of said second gusseted end toeach other and to another side of said second string zipper; and (j)inserting a second slider on said second string zipper after steps (h)and (i).
 38. The method as recited in claim 37, further comprising thestep of sealing respective portions of said monolithic film structuretogether along a portion of a second periphery to form a second enclosedreceptacle.
 39. The method as recited in claim 38, further comprisingthe step of placing a second mass of product on a second non-peripheralportion of said monolithic film structure before said second enclosedreceptacle is formed, said second mass of product being contained insidesaid second enclosed receptacle when the bag is finished.
 40. The methodas recited in claim 39, further comprising the step of cutting saidmonolithic film structure in a sealed zone that connects said first andsecond enclosed receptacles to form separate bags respective filled withsaid first and second masses of product.
 41. A method of manufacturing areclosable bag, comprising the following steps: (a) arranging andsealing film material to form a receptacle having a mouth and aninterior volume with a tamper-evident feature that blocks access to saidinterior volume; (b) prior to completion of said receptacle withtamper-evident feature, joining opposing portions of said film material,that will form said mouth of said receptacle, to respective backs offirst and second flangeless zipper strips; (c) aligning said first andsecond flangeless zipper strips with each other; and (d) after steps (b)and (c), mounting a slider onto said aligned first and second flangelesszipper strips with respective portions of said opposing portions of saidfilm material being disposed between respective side walls of saidslider and respective backs of said first and second flangeless zipperstrips.
 42. The method as recited in claim 41, further comprising thestep, performed prior to completion of said receptacle withtamper-evident feature, of placing a mass of product in contact with aportion said film material that will in part bound said interior volume.43. The method as recited in claim 41, wherein said sealing step in step(a) comprises applying a length of peel seal material to a portion ofsaid film material.
 44. The method as recited in claim 41, wherein saidarranging step in step (a) comprises folding a web of film material toform a generally M-shaped gusseted end, said opposing portions of saidfilm material being part of said generally M-shaped gusseted end. 45.The method as recited in claim 41, wherein said arranging step in step(a) comprises folding first and second webs of film material ofdifferent width into generally U-shaped structures having marginal edgesthat are generally aligned, said opposing portions of said film materialcomprising respective portions of said first and second webs proximal tosaid marginal edges.
 46. The method as recited in claim 41, wherein saidarranging step in step (a) comprises folding first and second portionsof film material to form first and second flaps, and said sealing stepin step (a) comprises joining a length of peel seal material to saidfirst and second flaps.
 47. The method as recited in claim 41, whereinsaid arranging step in step (a) comprises folding a web of film materialso that one marginal edge of said web is proximal to a portion of saidweb located at a predetermined distance from the other marginal edge ofsaid web, and said sealing step in step (a) comprises joining said onemarginal edge to said web portion located at a predetermined distancefrom said other marginal edge.
 48. The method as recited in claim 41,wherein said arranging step in step (a) comprises folding a web of filmmaterial so that one marginal edge of said web is proximal to a portionof said web located at a predetermined distance from the other marginaledge of said web, and said sealing step in step (a) comprises joining alength of peel seal material to said one marginal edge and said webportion located at a predetermined distance from said other marginaledge.
 49. The method as recited in claim 41, wherein said arranging stepin step (a) comprises folding a web of film material to form a generallyU-shaped structure, and placing a panel of film material with onemarginal edge of said panel generally aligned with one marginal edge ofsaid folded web and the other marginal edge of said panel being proximalto a portion of said folded web located at a predetermined distance fromthe other marginal edge of said folded web, and said sealing step instep (a) comprises joining a length of peel seal material to said othermarginal edge of said panel and to said portion of said folded weblocated at a predetermined distance from said other marginal edge ofsaid folded web, said opposing portions of said film material comprisingrespective portions of said folded web proximal to said marginal edgesof said folded web and a portion of said panel proximal to said onemarginal edge of said panel.
 50. The method as recited in claim 41,wherein step (a) comprises the following steps: folding a web of filmmaterial along first, second and third fold lines to form a serpentineprofile comprising first and second inner legs and first and secondouter legs, said first outer leg being connected to said first inner legat said first fold line, and said second outer leg being connected tosaid second inner leg at said third fold line, wherein confrontingportions of said first inner leg and said first outer leg form saidopposing portion joined to said first zipper strip, and confrontingportions of said second inner leg and said second outer leg form saidopposing portion joined to said second zipper strip; joining respectiveportions of said first and second inner legs of said web to form saidreceptacle; folding said first outer leg along a fourth fold line;folding said second outer leg along a fifth fold line; and joiningrespective opposing portions of said folded first and second outer legsto each other, thus forming a header that covers said zipper strips. 51.The bag as recited in claim 12, wherein said header comprises a hanghole.